Trump says the measure is "getting the government back on track."

The House on Thursday approved 210-206 President Trump’s proposal to revoke $15 billion in appropriated funds from federal agencies, the first such rescission package since the Clinton administration.

Most of the clawbacks would not affect agencies directly, as they deal with money that Congress appropriated that went unspent or that is no longer necessary. In some cases, Republicans have said, agencies could not spend the would-be rescinded money even if they wanted to. A Congressional Budget Office report on the package found the measure would save just $1 billion in actual outlays over the next 10 years.

In its own estimate, the Office of Management and Budget suggested the package would reduce outlays by $3 billion. CBO said it examined historical spending patterns and found much of the money the White House said should be rescinded would not have been spent anyway. Other parts of the package would claw back money unlikely to be spent because agencies no longer needed it for the purpose for which it was allocated, CBO said.

Various programs in the departments of Agriculture, Health and Human Services, Transportation and Treasury would face the hardest hits in actual spending cuts, CBO estimated. The agencies would absorb the cuts disproportionately in fiscal 2019, before gradually lessening until 2028. Treasury's Capital Magnet Fund, which helps credit unions finance affordable housing and community revitalization projects, would see its outlays reduced by $141 million.

The Energy Department, meanwhile, would face the largest rescission—a $4.1 billion cut to its Advanced Technology Vehicle Manufacturing loan program—but none of it would affect actual outlays.

Democrats opposed to the measure said the bill would cut from critical public investments, and called the the package "not a serious way to govern."

Republicans were "trying to take deconstructing government to a new level," Rep. Rosa DeLauro, D-Conn., a House Appropriations Committee member, said on the House floor Thursday. "They are doing so to pay for a tiny fraction of their $1.5 trillion tax cut for the rich."

The White House earlier this week tweaked its rescission proposal, but the changes were mostly minor and involved rounding errors or updates to funds remaining in various accounts. The White House in its update dropped its proposal to cut $252 million in remaining Ebola response funding.

The bill is part of a larger effort the White House is taking to cut federal appropriations, despite the president earlier this year signing a budget deal setting top-line funding levels for fiscal years 2018 and 2019. OMB Director Mick Mulvaney has in recent weeks sent a series of letters to congressional appropriators asking it to slash spending they have proposed allocating in their funding bills. On Tuesday, Trump ignored the much smaller total of actual savings in praising the package.

The HISTORIC Rescissions Package we’ve proposed would cut $15,000,000,000 in Wasteful Spending! We are getting our government back on track.

The package will now head to the Senate, where it will face a compressed schedule but only require a majority of votes for passage. Several Republicans in the upper chamber have expressed concerns about the bill, and even one dissenting vote would likely sink it.